Description: By alleviating the shortcomings of the production portfolio of variable renewable energy sources, the reliability of supply increases, significantly reduces the operating costs of the system and mitigates the need for capital-intensive construction of reserve production capacities. A sustainable transition to a decentralized, smart system emphasizes the need for innovative solutions in the prediction and management of the energy system and implies the implementation of advanced software solutions for management and optimization. In this context, digital technologies will prove to be crucial in enabling the energy transition. The increased use of electricity requires a control system that is able to correctly predict short-term variations in production and demand and perform real-time optimization. In accordance with the actions foreseen by REPowerEU and the European Green Plan, which envisage programs for the production of sustainable energy and the diversification of energy supply, but also in the context of the North Adriatic Hydrogen Valley project, of which the University of Rijeka is one of the initiators, and the Faculty of Engineering, University of Rijeka is a partner, and following all of the above, the proposed project has a double goal. 1. Conduct a techno-economic analysis of battery systems and facilities for the production and storage of green hydrogen. These technologies together with variable renewable energy sources (OIE) form an aggregated energy park. The analysis must provide insight into the technical characteristics of the system, their limitations, capital and variable costs (levelized cost of production and storage) and parameters of integration into the power system. The above data will be used in the creation of a digital model of the hydrogen production plant and energy storage, which will be used as input parameters for the second part of the project. 2. The second phase of the proposed project is the creation of optimization and prediction models for optimal use of battery and hydrogen energy storage within the power system and green hydrogen in the low-carbon transition of the northern Adriatic. The models will predict the short-term movement of defined parameters (such as energy demand and production of variable RES) based on which the aggregator’s operation will be optimized.